The National Transportation Safety Board is an independent Federal agency charged by Congress with investigating every civil aviation accident the United States. The NTSB determines the probable cause of the accidents and issues safety recommendations aimed at preventing future accidents. In addition, the NTSB carries out special studies concerning transportation safety and coordinates the resources of the Federal Government and other organizations to provide assistance to victims and their family members impacted by major transportation disasters.

The US Federal Aviation Administration confirmed it has launched an investigation after an Air Canada jet failed to respond to air traffic control's repeated requests to abort its landing. The incident occurred Sunday evening at San Francisco International Airport (SFO) less than four months after another Air Canada jet mistook a taxiway for a runway at the same airport, nearly causing one of the worst disasters in aviation history.

Air Canada Flight AC781, an Airbus A320 en route from Montreal, Canada, was on final approach to SFO when the incident took place. "Air traffic control cleared the flight to land on Runway 28R and the Air Canada crew acknowledged the instruction when they were approximately 6 miles away from the airport," an FAA spokesman told Business Insider in an email on Tuesday.
"The tower controller subsequently instructed the Air Canada crew multiple times to execute a go-around because he was not certain that a preceding arrival would be completely clear of the runway before the Air Canada jet reached the runway threshold."

After the crew failed to respond to the controller, the ATC used a red light gun in an attempt to alert the crew and get them to go around. "Flashing a light gun is standard protocol when anaircrew is not responding to radio instructions," the FAA said.
However, the flight did not respond to the light gun either. Instead, it proceeded to land on runway 28R at 9:26 pm.
After landing, the Air Canada pilots told the tower that they experienced a radio problem. Fortunately, no one was injured as the preceding aircraft had cleared the runway by the time AC781 landed.

In a statement to Business Insider, an Air Canada spokesman wrote: Air Canada flight AC781, an Airbus A320 was traveling from Montreal to San Francisco on the evening of Oct. 22. After receiving proper clearance to land it proceeded to do so and landed normally. Upon landing the crew was informed the tower had attempted unsuccessfully to contact the aircraft, however, the message was not received by the crew. Air Canada is investigating the circumstances. In July, Air Canada Flight AC759 mistook a taxiway for a runway at SFO, nearly landed on top of a row of airliners waiting in line to take off. According to the National Transportation Safety Board, that Air Canada jet was less than 60 ft from the ground before it climbed to safety.

SAN FRANCISCO INT’L AIRPORT (KPIX 5) – The Federal Aviation Administration is investigating another incident involving the landing of an Air Canada flight at San Francisco International Airport on Sunday night.

According to the FAA, Flight 781 from Montreal was cleared to land on runway 28-R by air traffic control. The tower then then repeatedly instructed the crew to execute a “go-around,” since officials were unsure that another plane would be clear of the runway. Within 30 seconds, the flight crew was told to go around five times. Officials said the Air Canada crew did not acknowledge the instructions after being told multiple times to go around, prompting an airport supervisor to use a red light gun to alert the crew.

The Air Canada jet was able to land safely at 9:26 p.m. A radar replay showed the other plane was clear of the runway when the Air Canada jet landed. Afterwards, the crew told the tower they had a radio problem. Retired Captain Ross Aimer says he flew into SFO hundreds of times during his career. His explanation for this confusion? “I’m afraid these fellows were almost clueless,” said Aimer.”I would look back at these guys scheduling practice, see if they’re dead tired or whatever it is. This is sloppy radio discipline.”

That was unsettling news for air Canada passengers like Paul Child who are already nervous about flying. “I just don’t want anything to go wrong, to be honest with you,” said Child. “And I’ve got to fly back from Toronto next week with Air Canada. So yeah, it’s a bit of a worry.” In a written statement, Air Canada told KPIX 5, “After receiving proper clearance to land it proceeded to do so and landed normally. Upon landing the crew was informed the tower had attempted unsuccessfully to contact the aircraft, however the message was not received by the crew. Air Canada is investigating the circumstances.”

Sunday night’s incident took place three months after another Air Canada jet came within seconds of crashing into two other planes full of passengers, when the pilot almost landed on the taxiway. In that case, the plane made a go-around and landed safely.